FERGUSON - Demonstrators in the U.S. town of Ferguson, Missouri, on Saturday marked two weeks since a white policeman shot an unarmed black teenager to death, holding smaller, quieter protests as supporters of the officer rallied separately and called the shooting justified.

The demonstrations remained peaceful as darkness fell, marking the fourth night of relative calm for the St. Louis suburb following nightly spasms of unrest since Michael Brown, 18, was shot by Ferguson police officer Darren Wilson on Aug. 9.

The area's main street was open to traffic and police presence was down sharply from just 24 hours earlier.

Shortly before midnight, police responded to a small group playing music loudly outside a McDonald's, resulting in some tense moments that led to three people being arrested. The crowd moved on as urged by police and a civilian with a megaphone.

Authorities had arrested dozens nightly as police clashed with demonstrators, focusing attention on often-troubled U.S. race relations. Police came under sharp criticism for making mass arrests and using heavy-handed tactics and military gear widely seen as provoking more anger and violence.

President Barack Obama has ordered a review of the distribution of military hardware to state and local police out of concern over how such equipment has been used in Ferguson, a senior administration official said on Saturday.

The White House also announced that three presidential aides would attend Brown's funeral on Monday.

On Saturday morning, about 70 people marked the two weeks since Brown's death by praying at a makeshift memorial where he was shot and launching into a rendition of "We Shall Overcome" at the time when the fatal encounter began.

Tracey Stewart-Parks, 52, who works in accounting for a health care firm, carried a sign that read "Mike Brown was someone's son - I walk for their son." She said something similar could have happened to any of her four sons.

"All of them have had to learn the rules of driving black and they're lucky it wasn't them," she said. "This has been a long time coming and I do believe we shall overcome. It's time to rip the Band-Aid off this old wound. It's time for change."

In the afternoon, some 500 people braved triple-digit heat to march in a St. Louis County rally, led by the National Association for the Advancement of Colored People (NAACP), wearing brightly colored T-shirts, many holding umbrellas for shade as temperatures hit 98 degrees Fahrenheit (37 Celsius).

Missouri Highway Patrol Captain Ron Johnson, commander of the police response to the demonstrations, who is black, and St. Louis County Police Chief Jon Belmar, who is white, joined the head of the march.

'HIS STORY IS COMING OUT'

About 14 miles (22 km) away in St. Louis, dozens of supporters of Wilson gathered at Barney's Sports Pub to raise money for the officer's family. Some held signs that said "innocent until proven guilty" and asked drivers to honk their horns as they passed in support, which many did.

"We are here to support you, Officer Wilson, and we've got your back. He has been vilified in the news but his story is coming out," St. Louis resident Mark Rodebaugh said.

A statement from rally organizers said in part, "Our mission is to formally declare that we share the united belief that Officer Wilson's actions on Aug. 9 were warranted and justified and he has our unwavering support."

Despite the calm of recent nights, Derrick Rhodes, 45, who owns the Country Girl Pie House in St. Louis, remained wary.

"It all depends on the verdict of the officer. If he isn't convicted they will be back in uproar," Rhodes said.

Little information has been released about the investigation. A grand jury began hearing evidence on Wednesday, process the county prosecutor said could take until mid-October.

The National Guard began a gradual withdrawal from Ferguson on Friday but authorities remain braced for a possible flare-up of civil disturbances ahead of Brown's funeral. Local activists, clergy, U.S. civil rights workers and community activists from around the country have set up shop in Ferguson and say they plan to stay for an extended period.

In part they want to work on ways to improve Ferguson, a community of 21,000 that is about 70 percent African American but where almost all the police and politicians are white.

A St. Louis County officer, Dan Page, on Friday was placed in an administrative position pending an internal investigation after a video surfaced in which he boasted of being "a killer," made disparaging remarks about Muslims and expressed the view that the United States was on the verge of collapse.

Belmar called the comments by Page, a 35-year force veteran and former U.S. serviceman, "bizarre" and unacceptable.

Two days earlier, an officer from the town of St. Ann was suspended indefinitely for pointing a semi-automatic assault rifle at a peaceful demonstrator and yelling obscenities.

Lesley McSpadden (R) and Michael Brown Sr. (L), parents of 18-year-old Michael Brown, listen to speakers during a rally convened in reaction to the shooting of their son, in Ferguson, Missouri August 17, 2014. (REUTERS/Mark Kauzlarich)